Various types of grinders for pepper and other spices are known. In these devices, the grinding occurs through friction between a fixed part and a mobile part. The two parts have, on the respective contact surfaces, a toothing or corrugations with a sharp edge that are intended to grind a product through friction (for example, pepper corns). In reality said surfaces are not in contact, but are spaced so as to create a gap between them defining the end grain-size of the ground product. The grinding occurs by making the mobile part rotate with respect to the fixed part, so that the pieces of the product are “held” between the teeth of the grinder and are minutely chopped by them up to the desired size.
The need of grinding different types of products (such as various spices, dried mushrooms, chocolate, coffee, etc.), often having irregular sizes, has led to the need of optimising the profile of the grinder and counter-grinder toothings, so as to prevent the smaller or bigger pieces of product from becoming stuck in between the teeth. However, this type of grinder, on the market for several years, does not allow the grinding grain-size to be adjusted, as on the other hand may be desirable in some culinary applications.
European patent EP 1 696 775 B1 solves this problem by providing a grinder in which the distance between the grinding surfaces can be adjusted by making the grinder slide in an axial direction with respect to the counter-grinder.
However, such a solution, in use, was found to have some drawbacks. Indeed, especially after use over quite a long time, the snap sliding of the grinder with respect to the counter-grinder tends to stiffen until it locks into one of the adjustment positions.